render-oss/render-postgres

Render Managed PostgreSQL

This skill covers Managed Postgres on Render: how to connect, what cannot change after creation, storage behavior, limits, HA, replicas, and safe deletion. Deep dives live under references/.

When to Use

Apply this skill when the user:

• Configures Postgres for an app on Render (URLs, TLS, pooling)
• Creates or changes a database, plan, disk, or replicas
• Asks about backups, PITR, exports, or deleting a database
• Hits connection limits, SSL errors, or latency between services and DB
• Authors Blueprint databases / readReplicas or wires fromDatabase

For deploy flows and Blueprint basics, see render-deploy and render-blueprints. For private networking between services, see render-networking. For env var patterns, see render-env-vars.

Connection Patterns

Render exposes two connection URLs for the same logical database:

| URL | Use when | TLS | |-----|----------|-----| | Internal | App or service on Render in the same region and workspace | Not required (private network) | | External | Local development, CI, or tools outside Render | Required (TLS 1.2+) |

Always prefer the internal URL for Render-hosted apps so traffic stays on Render’s network and avoids extra latency and public egress patterns.

• IP allow list applies to external access only. Same-region Render services use the internal URL regardless of the allow list.
• External clients must use TLS; misconfigured clients often show SSL handshake or sslmode errors.

URL formats, Dashboard locations, Blueprint fromDatabase, pooling, and common mistakes: references/connection-guide.md.

Creation and Setup

• Instance display name: Can be changed later (where the Dashboard allows renaming the resource).
• Immutable after creation: databaseName, database user, region, PostgreSQL major version. Plan these before create; changing them requires a new database and migration.
• Storage size: 1 GB or multiples of 5 GB when provisioning.

Wire apps with Blueprint fromDatabase using property: connectionString (or host, port, user, password, database individually). See render-blueprints.

Multiple logical databases

You can run CREATE DATABASE new_db; in psql on the same instance. Host, port, and credentials stay the same; only the database name in the URL path changes (e.g. .../myapp vs .../new_db).

Storage Management

• Autoscaling: When disk use reaches roughly ~90%, Render can grow storage by about ~50%, rounded up to the next 5 GB multiple, up to 16 TB max.
• Cannot shrink disk after an increase.
• Cooldown: After a storage increase, you cannot increase again for 12 hours.
• Over limit / unhealthy: If disk is over the configured limit, the database can become unhealthy; Render may suspend it until resolved.

Monitor disk and plan exports or cleanup before you hit hard limits. Backup and restore options: references/backup-and-recovery.md.

Connection Limits

Maximum connections depend on instance RAM (current-generation plans):

| RAM | Max connections (typical) | |-----|---------------------------| | Under 8 GB | 100 | | 8 GB | 200 | | 16 GB | 300 | | 32 GB and above | 500 |

Legacy database plans may have lower limits; confirm in the Dashboard or API for the specific plan.

Render does not provide a built-in pooler; use application-side pooling (framework pools, PgBouncer, pgpool, etc.). Limits are hard—exhausting them causes connection errors. More detail: references/connection-guide.md and references/performance-tuning.md.

High Availability

High availability (HA) is available when:

• Workspace is Professional or higher, and
• Database plan is Pro or higher, and
• PostgreSQL 13+

Instance type changes cause brief downtime. With HA, downtime is typically less than without HA (often on the order of minutes without HA—exact duration depends on plan and operation).

One-way migration off legacy types: After moving to current-generation instance types, you cannot move back to legacy instance types.

Read Replicas

• Up to 5 read replicas per database.
• In Blueprints, declare replicas under readReplicas as a list of names.
• CAUTION — declarative sync:
  • An empty readReplicas list can destroy all existing replicas.
  • Name mismatches between the Blueprint and live replicas can create new replicas and remove replicas whose names are no longer listed.

Always treat readReplicas as authoritative desired state, not additive-only.

Useful MCP Commands

Use the Render MCP tools (names may vary slightly by integration; align with your server’s tool list):

| Goal | Tool / pattern | |------|----------------| | List databases | list_postgres_instances | | Instance details | get_postgres with postgresId | | Read-only SQL | query_render_postgres with postgresId and sql | | Connection load | get_metrics with resourceId (Postgres ID) and metricTypes: ["active_connections"] |

query_render_postgres runs in a read-only transaction and opens a new connection per query—do not use it as a substitute for app pooling.

Shorthand (same tools): list_postgres_instances(), get_postgres(postgresId), query_render_postgres(postgresId, sql), get_metrics(resourceId, metricTypes: ["active_connections"]).

Deleting and Data Safety

• Backups and snapshots are not retained after you delete the database. Export first (pg_dump, Dashboard restore workflow from existing backups, etc.).
• Before destructive actions, confirm retention and recovery paths in references/backup-and-recovery.md.

References

| Document | Contents | |----------|----------| | references/connection-guide.md | Internal vs external URLs, SSL, allow list, Blueprint wiring, pooling, multi-database URLs, troubleshooting | | references/backup-and-recovery.md | Snapshots, PITR, pg_dump / pg_restore, restore flows, deletion, cross-region | | references/performance-tuning.md | pg_stat_statements, indexes, bloat, EXPLAIN ANALYZE, metrics, scaling |

Related Skills

• render-deploy — End-to-end deploy, services, and MCP/Dashboard flows
• render-blueprints — databases, fromDatabase, readReplicas, immutable fields
• render-networking — Private services, regions, and how traffic routes between resources
• render-env-vars — Storing DATABASE_URL and secret wiring patterns